Discreet Render Format (DRF) file created by VIZ Render, a program included with older versions of Autodesk Architecture; saves a rendered image of buildings or other modeled structures; can be opened in 3ds Max, but can only be created by VIZ Render.

After opening a DRF file in 3ds Max, you must save it as a .MAX file since saving DRF files is not supported.

Temporary file created by Delphi, a software development programming language and IDE; saves package requirement information when a project is compiled with packages; used during the software building process.

DRF files are sometimes referenced in Delphi error messages when a program cannot located or create the file in a temporary location. To fix this, you may be able to explicitly rebuild the application or make sure the temporary location is accessible.